.\" -*- nroff -*-
.\" Copyright 2010 Cisco Systems, Inc.  All rights reserved.
.\" Copyright 2006-2008 Sun Microsystems, Inc.
.\" Copyright (c) 1996 Thinking Machines Corporation
.\" Copyright 2015-2016 Research Organization for Information Science
.\"                     and Technology (RIST). All rights reserved.
.\" Copyright (c) 2020      Google, LLC. All rights reserved.
.\" $COPYRIGHT$
.TH MPI_File_get_atomicity 3 "#OMPI_DATE#" "#PACKAGE_VERSION#" "#PACKAGE_NAME#"
.SH NAME
\fBMPI_File_get_atomicity\fP \- Returns current consistency semantics for data-access operations.

.SH SYNTAX
.ft R
.nf
.SH C Syntax
.nf
#include <mpi.h>
int MPI_File_get_atomicity(MPI_File \fIfh\fP, int \fI*flag\fP)

.fi
.SH Fortran Syntax
.nf
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_FILE_GET_ATOMICITY(\fIFH\fP, \fIFLAG\fP, \fIIERROR\fP)
	INTEGER	\fIFH, IERROR\fP
	LOGICAL	\fIFLAG\fP

.fi
.SH Fortran 2008 Syntax
.nf
USE mpi_f08
MPI_File_get_atomicity(\fIfh\fP, \fIflag\fP, \fIierror\fP)
	TYPE(MPI_File), INTENT(IN) :: \fIfh\fP
	LOGICAL, INTENT(OUT) :: \fIflag\fP
	INTEGER, OPTIONAL, INTENT(OUT) :: \fIierror\fP

.fi
.SH INPUT PARAMETER
.ft R
.TP 1i
fh
File handle (handle).

.SH OUTPUT PARAMETER
.ft R
.TP 1i
flag
true if atomic mode is enabled, false if nonatomic mode is enabled (boolean).
.TP 1i
IERROR
Fortran only: Error status (integer).

.SH DESCRIPTION
.ft R
MPI_File_get_atomicity returns the current consistency semantics for
data access operations on the set of file handles created by one
collective MPI_File_open. If \fIflag\fP is
.I true,
atomic mode is currently enabled; if
.I flag
is
.I false,
nonatomic mode is currently enabled.

.SH ERRORS
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument.
.sp
Before the error value is returned, the current MPI error handler is
called. For MPI I/O function errors, the default error handler is set to MPI_ERRORS_RETURN. The error handler may be changed with MPI_File_set_errhandler; the predefined error handler MPI_ERRORS_ARE_FATAL may be used to make I/O errors fatal. Note that MPI does not guarantee that an MPI program can continue past an error.

